Date of Award:

5-2000

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Civil and Environmental Engineering

Committee Chair(s)

Thomas B. Hardy

Committee

Thomas B. Hardy

Committee

David K. Stevens

Committee

Christopher M. U. Neale

Committee

D. Richard Cutler

Abstract

Several methods were undertaken to develop a rapid assessment methodology for predicting the relative magnitude of available habitat as measured by normalized weighted useable area, NWUA, based on limited watershed characteristics and/or limited field data observations. Data from 170 river sites primarily in Idaho, comprising 645 cross sections, were used. The three methodologies considered were generalized linear models (GLM), generalized additive models (GAM), and a newly developed comparative cross-section method (CCM). The GLM and GAM methods relied on a combination of field data and information readily obtained or derivable using geographic information systems (GIS). They also require the delineation of specific habitat units such as runs, pools, and riffles. These methods provided good predictive capabilities in pools but performed somewhat poorer in run and riffle type habitat units. The utility of these approaches suffered from the necessity to develop predictive equations for each 5 percent increment of discharge simulated between 5 and 100 percent of bankfull discharge. Although results from the GLM and GAM demonstrated the utility of these approaches, an alternative method (CCM) that obviates the need for, and reliance on, watershed characteristics eliminates the need for proper habitat unit delineations into run, pools, or riffles, and minimized site-specific field data were developed. CCM was shown to work well for pool habitat units but also provided improved predictive capabilities in runs and riffles. The CCM approach produced very good predictive capabilities for NWUA curves, for between 80 and 90 percent of all cross sections evaluated. All three approaches suffer from lack of a quantitative way of determining whether the prediction of available habitat as a function of discharge at a particular site was good in the absence of validation data. However, the CCM approach relies upon field data collection that can be analyzed using such analytical tools as the R2Cross methodology that can provide limited validation data.

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